The invention provides a method of routing using an offboard navigation system for motor vehicles, in which road points, at which there is a road junction, and also the road distance between adjacent road points on a calculated route are stored in a memory element in the vehicle. Preferably, only those road points which are also turnoff points are stored. The distance from the next turnoff point at which a turnoff maneuver is to be effected is determined by comparing the distance covered since the last turnoff point with a stored value for the road distance between the adjacent turnoff points. If a minimum value for the distance from the next turnoff point has not been reached, a driving instruction is output. The method requires only a small volume of data and an odometer for position finding.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of routing a vehicle using a navigation system in the vehicle which comprises a control unit, and an input unit and an output unit which are connected to the control unit, an odometer, and a communication appliance for communicating with a central station which is located outside the vehicle and contains a digital road map having data, comprising the steps of: calculating a route using a starting point and a destination and the data of the digital road map, wherein characteristic road points, at which there is a road junction, and the road distance between adjacent characteristic road points on the route are stored in a memory element in the vehicle, on reaching a characteristic road point, beginning a distance comparison between a distance from the road point reached to the next road point and a distance traveled from the road point reached, wherein the distance from the last road point reached is continually ascertained by the odometer in the vehicle, and the distance ascertained in this manner is compared with a stored distance between the last road point reached and the next road point on the route, and if a minimum value for the distance from the next road point has not been reached, a driving instruction is output.
2. The method of claim 1 , wherein the road points are exclusively turnoff points on the calculated route.
3. The method of claim 2 , wherein the distance from the next turnoff point is output.
4. The method of claim 1 , wherein the odometer is the only means used to determine the distance from the next road point.
5. The method of claim 1 , wherein the starting point and the destination are transmitted from the vehicle to the central station, the route is calculated outside the vehicle and the characteristic road points are transmitted to the vehicle.
6. The method of claim 1 , wherein the starting point is ascertained by satellite navigation.
7. The method of claim 1 , wherein a turnoff maneuver at a road point is recognized by means of a direction sensor.
8. The method of claim 1 , wherein current traffic information is taken into account for route calculation.
9. The method of claim 8 , wherein the road points and the distances between the road points are updated by route recalculation as traffic situations change.
10. The method of claim 1 , wherein the output device is part of an audio system.
11. The method of claim 1 , wherein the communication appliance transmits received data to the control unit over a short-haul radio link.
12. The method of claim 1 , wherein the minimum value for the distance at which a driving instruction is output when it has not been reached is prescribed depending on speed.
13. A method of routing a vehicle using a navigation system in the vehicle which comprises a control unit, and an input unit and an output unit which are connected to the control unit, an odometer, and a communication appliance for communicating with a central station which is located outside the vehicle and contains a digital road map having data, comprising the steps of: calculating a route outside the vehicle using a starting point and a destination which are transmitted from the vehicle to the central station, and the data of the digital road map, wherein characteristic road points are transmitted to the vehicle, said characteristic road points representing a road junction, and a road distance between adjacent characteristic road points on the route are stored in a memory element in the vehicle, on reaching a characteristic road point, beginning a distance comparison between a distance from the road point reached to the next road point and a distance traveled from the road point reached, wherein the distance from the last road point reached is continually ascertained by the odometer in the vehicle, and the distance ascertained in this manner is compared with a stored distance between the last road point reached and the next road point on the route, and if a minimum value for the distance from the next road point has not been reached, a driving instruction is output.
14. The method of claim 13 , wherein the road points are exclusively turnoff points on the calculated route.
15. The method of claim 14 , wherein the distance from the next turnoff point is output.
16. The method of claim 13 , wherein the starting point is ascertained by satellite navigation.
17. A method of routing a vehicle using a navigation system in the vehicle which comprises a control unit, and an input unit and an output unit which are connected to the control unit, an odometer, and a communication appliance for communicating with a central station which is located outside the vehicle and contains a digital road map having data, comprising the steps of: calculating a route using a starting point and a destination and the data of the digital road map, wherein characteristic road points, at which there is a road junction, and the road distance between adjacent characteristic road points on the route are stored in a memory element in the vehicle, on reaching a characteristic road point, beginning a distance comparison between a distance from the road point reached to the next road point and a distance traveled from the road point reached, wherein the distance from the last road point reached is continually ascertained by the odometer in the vehicle, and the distance ascertained in this manner is compared with a stored distance between the last road point reached and the next road point on the route, if a minimum value for the distance from the next road point has not been reached, a driving instruction is output, and wherein current traffic information is taken into account for route calculation.
18. The method of claim 17 , wherein the road points and the distances between the road points are updated by route recalculation as traffic situations change.
19. The method of claim 17 , wherein the road points are exclusively turnoff points on the calculated route.
20. The method of claim 17 , wherein the starting point is ascertained by satellite navigation.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
February 28, 2001
July 9, 2002
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